248 STRUCTURE OF THE 



form a common trunk, but larger by the additional lymphatic 

 vessels it receives from the cells of the gland. See Plate VI, 

 fig. 3. 



SECT. 8. Sometimes only one lymphatic vessel, and some- 

 times three or four of them, pass through the same gland, in 

 the manner described above, and these either pass through 

 other glands in the same way, or continue their course on to 

 the thoracic duct. Vide Plate VI, fig. 1. Sometimes we ob- 

 serve a single lymphatic pass by all the glands, without entering 

 any one of them, and continue on to the thoracic duct. This 

 observation may perhaps account for the venereal, variolous, 

 or other poisons, 'being sometimes taken into the habit, with- 

 out inflaming a lymphatic gland in its passage." See page 129. 



SECT. 9. In Sect. 3 we. found that each lymphatic gland 

 is a congeries of. vessels, and in Sect. 7 we observed that 

 some lymphatic vessels arose from the cells of the gland; but 

 here we do not mean those appearances which have been called 

 cellular 1 (and that are in reality only little eminences, formed 

 by the bending of one vessel round another), but other cells 

 which really do exist in the substance of the gland, and are so 

 very small as to become visible only by the assistance of the 

 microscope. 



If we inject 2 a lymphatic gland with mercury, or inflate it 

 with air, an irregular appearance is produced, very much re- 

 sembling cells ; and if a gland prepared in this manner is 

 dried and cut through, at first sight it looks like a honeycomb, 

 but if we examine it more attentively, we shall find this cellular 

 appearance evidently made of convoluted vessels ; and in by far 

 the greater part of lymphatic glands, that we prepare, the 

 subdivision of the lymphatic vessels into smaller and smaller 

 branches, and not into cells, is apparent to the naked eye. 

 Vide Plate VI, figs. 3, and 4. 



SECT. 10. The cellular appearance in the lymphatic gland 

 is, I think, probably a deception, which may happen in the 

 following way. The very small lymphatic vessels are very 

 much convoluted, and running in a serpentine direction one 

 over the other, a part of one vessel is covered by that part of 



1 M. de Haller, Elem. Physiolog. torn, i, p. 183. 



2 Vide Plate vi, fig. 3. 



